The invention relates to a film-transport mechanism constituting an improvement upon the mechanism disclosed in commonly owned U.S. Pat. No. 3,810,219. The camera provided with that mechanism includes a manually driven input member supplying film-transport force coupled to the film take-up spool, and a device for assuring that the film is advanced by exactly the length of one frame, and utilizes a film transport transmission designed as a rotary transmission having two output components. One output component is a film drive member and the other output component is blocked during film-frame advancement by means of a locking mechanism and thereupon released, whereafter the film drive member becomes blocked. In particular, a perforation sensor enters into a film perforation near completion of the film-frame advancement and causes the locking mechanism to release the first output component, the subsequent arresting of the other output component being the result of the resistance of the film to further transport (provided by film friction and/or by detention of the film by the perforation sensor and/or by inherent friction of the transmission itself).